Products such as liquid medicaments and toiletries have long been packaged in "squeeze" containers which, along with a spray nozzle fitted to the container neck, dispense the product in spray form. The "squeeze" containers are generally made of a thermoplastic material and have sidewalls which are resiliently deformable. The spray nozzle is fitted with a dip tube which extends from a point adjacent the nozzle's gas-liquid mixing chamber to a point beneath the level of the product in the container. A nozzle dispensing orifice contiguous with the mixing chamber provides the pathway for the liquid product to be dispensed from the container.
In use, the container is squeezed, usually by applying finger pressure to the container sidewalls. Such squeezing deforms the container so that its interior volume is decreased. Concomitant with the decrease in the interior volume, there is an increase in internal pressure. When the container is in a substantially upright position, product, under the influence of the increased pressure, is forced up the dip tube into the gas-liquid mixing chamber. Simultaneously, gas, usually air within the container, is forced into the gas-liquid mixing chamber to mix with the product and to cause same to be dispensed through the dispensing orifice as a spray. When the container is in the substantially inverted position, the gas and product are still routed to the gas-liquid mixing chamber. However, their routes are reversed--the gas being routed via the dip tube and the product being routed via the route followed by the gas when the container is in the upright position. This rerouting results, in most conventional spray nozzles, in the product being dispensed as a stream. When the product is a medicament, e.g., nasal spray, mis-dosage can occur. If the product is a toiletry, product waste and misapplication occur.
The inability to provide a spray dispensing mode in the inverted position is a result of poor gas-product mixing which is believed due to the configuration of the gas-liquid mixing chamber and the relative amounts of gas and product reaching the chamber. In the upright position, the mixing chamber configuration provides adequate gas product mixing while in the inverted position, such mixing is inadequate.
Therefore, it is an object of this invention to provide a spray nozzle for use on "squeeze" containers which nozzles have a gas-liquid mixing chamber which is configured to produce a spray dispensing mode irrespsective of container position.